builder/virtualbox,vmware: work if port range for HTTP is 0 [GH-53]

CHANGELOG.md

@@ -4,6 +4,10 @@ BUG FIXES:
 
 * core: plugins listen explicitly on 127.0.0.1, fixing odd hangs. [GH-37]
 * virtualbox: `boot_wait` defaults to "10s" rather than 0. [GH-44]
+* virtualbox: if `http_port_min` and max are the same, it will no longer
+  panic [GH-53]
+* vmware: if `http_port_min` and max are the same, it will no longer
+  panic [GH-53]
 
 ## 0.1.0 (June 28, 2013)
 

builder/virtualbox/step_http_server.go

@@ -38,7 +38,14 @@ func (s *stepHTTPServer) Run(state map[string]interface{}) multistep.StepAction
 	portRange := int(config.HTTPPortMax - config.HTTPPortMin)
 	for {
 		var err error
-		httpPort = uint(rand.Intn(portRange)) + config.HTTPPortMin
+		var offset uint = 0
+
+		if portRange > 0 {
+			// Intn will panic if portRange == 0, so we do a check.
+			offset = uint(rand.Intn(portRange))
+		}
+
+		httpPort = offset + config.HTTPPortMin
 		httpAddr = fmt.Sprintf(":%d", httpPort)
 		log.Printf("Trying port: %d", httpPort)
 		s.l, err = net.Listen("tcp", httpAddr)

builder/vmware/step_http_server.go

@@ -38,7 +38,14 @@ func (s *stepHTTPServer) Run(state map[string]interface{}) multistep.StepAction
 	portRange := int(config.HTTPPortMax - config.HTTPPortMin)
 	for {
 		var err error
-		httpPort = uint(rand.Intn(portRange)) + config.HTTPPortMin
+		var offset uint = 0
+
+		if portRange > 0 {
+			// Intn will panic if portRange == 0, so we do a check.
+			offset = uint(rand.Intn(portRange))
+		}
+
+		httpPort = offset + config.HTTPPortMin
 		httpAddr = fmt.Sprintf(":%d", httpPort)
 		log.Printf("Trying port: %d", httpPort)
 		s.l, err = net.Listen("tcp", httpAddr)